Recent technological advances in mannnd and unmanned undersea v have overcome some the limitations of divers and diving equipment, without vehicle, divers often became sluggish and their mental concentration became limited Because of undersea pressure which affected their speech organai communication among divers was difficult impossible. But today, most make observations by means of instruments which are lowered into the ocean or from samples taken from the water. Direct observations of the are made not only vers but also by deep diving of these submarines can dive to depths of more than seven miles and cruise at depths of fifteen thousand feet. Radio. buoys can be operated by remote control in order to transmit information back to laboratories, including data about water temperature, currents, and land-based weather